Intermittent breath holding during moderate bicycle exercise provokes consistent changes in muscle oxygenation and greater blood lactate response

Aim. This study examined the effect of intermittent breath holding (IBH) on physiological response, including oxygenation in working muscle, to moderate-intensity exercise. Methods. Thirteen men performed bicycle exercise for 5 min at 65% of peak oxygen uptake with normal breathing (NB) and with IBH. Muscle oxygenation, concentration changes of oxyhemoglobin (Delta Oxy-Hb), deoxyhemoglobin (Delta Deoxy-Hb) and total hemoglobin (Delta Total-Hb), in the right vastus lateralis were continuously monitored using near-infrared spectroscopy (NIRS). Finger capillary blood samples were taken after exercise for analyzing blood lactate concentration (BLa). Results. NIRS parameters showed acute changes to each BH episode in the EBH condition (Total-Hb and Delta Oxy-Hb decreased, Delta Deoxy-Hb increased). Accordingly, in the IBH condition, Delta Oxy-Hb was lower (P<0.05) and Delta Deoxy-Hb was higher (P<0.05) compared to that in the NB condition, whereas there was no difference in Delta Total-Hb in the both conditions. BLa levels were greater (P<0.05) in the IBH condition compare to the NB condition. Conclusion. These results suggest that IBH during moderate-intensity exercise provokes consistent changes in muscle oxygenation, leading to lower tissue oxygenation. Our data also indicate that exercise with IBH induces higher BLa.